What will make engine idle high after warming up.

ANONYMOUS

2003 CHEVROLET MALIBU

68,000 MILES

What will make engine idle high after warming up but idle fine when first started. Changed idle air control and throttle position sensor and still the same so had dealership test it and they say pcm bad. So called to get one and the man said that it could be the bcm insted of pcm. Can the bcm cause this problem to?